Effect of indinavir used alone or in double or triple combination with AZT and ddC on human immune functions

Indinavir (IDV) is a potent and selective human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) widely used in antiretroviral therapy, but its effects on the immune system are relatively unknown. In this study we have investigated the in vitro effect of IDV on normal human peripheral blood mononuclear cells (PBMC). We used the drug alone or in double and triple combination with AZT and ddC to assess whether IDV interferes with the previously observed immunomodulatory effects induced by AZT and ddC. We found that proliferative response, induction of immunoglobulins (Ig) production and cytokine production was not modulated by IDV. More importantly, IDV used in double or triple combination with AZT and ddC, does not further strenghten the inhibition of proliferative response induced by AZT and is able to abrogate the inhibitory effect induced by ddC on proliferative response. Similarly, IDV/AZT, IDV/ddC and IDV/AZT/ddC combinations does not strenghten the modulation of TNF-alpha, IFN-gamma and IL-4 induced by AZT, ddC and AZT/ddC. On the other hand, IDV neutralizes the up-regulating effects of AZT on IL-2 production while the up-regulating effects of ddC on IL-2 production is not affected. These data suggest that IDV used in combination with AZT and ddC did not add any further immunotoxicity.     

Serious Adverse Events Are Uncommon with Combination Neonatal Antiretroviral Prophylaxis: A Retrospective Case Review

Six weeks of zidovudine (ZDV) is recommended for postnatal prophylaxis of HIV-exposed infants, but combination antiretrovirals are indicated if HIV transmission risk is increased. We investigated the frequency and severity of adverse events (AE) in infants receiving multiple drug prophylaxis compared to ZDV alone. In this retrospective review of 148 HIV-exposed uninfected infants born between 1997–2009, we determined clinical and laboratory AE that occurred between days of life 8–42. Thirty-six infants received combination prophylaxis; among those, a three-drug regimen containing ZDV, lamivudine, and nevirapine was most common (53%). Rates of laboratory AE grade ≥1 were as follows for the combination prophylaxis and ZDV alone groups, respectively: neutropenia 55% and 39%; anemia 50% and 39%; thrombocytopenia 0 and 3%; elevated aspartate aminotransferase 3% and 3%; elevated alanine aminotransferase 0 and 1%; hyperbilirubinemia 19% and 42%. Anemia occurred more frequently in infants who received three-drug prophylaxis compared to infants who received ZDV alone (63% vs. 39%, p = 0.04); all anemia AE were grade 1 or 2 in the three-drug prophylaxis group. Overall, 75% of infants on combination prophylaxis and 66% of infants on ZDV alone developed grade ≥1 AE (p = 0.32), and 17% of infants in either group developed grade ≥3 AE. Stavudine was substituted for ZDV in 23 infants due to anemia or neutropenia. After this antiretroviral change, 50% of evaluable infants demonstrated improvement in AE grade, and 25% had no change. In conclusion, low grade anemia, neutropenia, and hyperbilirubinemia occurred frequently regardless of the prophylactic regimen, but serious AE were uncommon. Although most AE were typical of ZDV toxicity, the combination of ZDV with lamivudine and nevirapine resulted in an increased frequency of low-grade anemia. Further studies are needed to identify prophylactic regimens with less toxicity for infants born to HIV-infected mothers.     

Embryotoxic effects of sodium arsenite and sodium arsenate on mouse embryos in culture

Embryotoxic effects of two inorganic arsenic compounds, sodium arsenite (Asi) and sodium arsenate (Asa), on the development of mouse embryos during early organogenesis were studied using the whole embryo culture technique. Embryos with three to five somites exposed to 1-40 microM Asi or to 10-400 microM Asa were cultured for 48 hours and their development was compared with that of control embryos. Asi proved to be teratogenic between 3 and 4 microM and embryolethal at higher concentrations; Asa had similar activity but at concentrations ten times higher than for Asi. Both compounds produced a growth retardation and a similar pattern of defects. Growth retardation was indicated by a statistically significant reduction in crown-rump length, head length, and yolk sac diameter. Abnormal embryos were characterized by hypoplasia of the prosencephalon with open neural tube, hydropericardium, somite abnormalities, and failure of development of limb buds and sensory placodes. These results confirm that both Asa and Asi are embryotoxic compounds and that the Asi activity occurs at concentrations ten times lower than for Asa. Our results suggest that in humans both of these compounds may be involved in part of "unaccountable" early abortions and malformations claimed to be due to the toxicity of heavy metals.     

Pregnancy outcome and placenta pathology in Plasmodium berghei ANKA infected mice reproduce the pathogenesis of severe malaria in pregnant women

Pregnancy-associated malaria (PAM) is expressed in a range of clinical complications that include increased disease severity in pregnant women, decreased fetal viability, intra-uterine growth retardation, low birth weight and infant mortality. The physiopathology of malaria in pregnancy is difficult to scrutinize and attempts were made in the past to use animal models for pregnancy malaria studies. Here, we describe a comprehensive mouse experimental model that recapitulates many of the pathological and clinical features typical of human severe malaria in pregnancy. We used P. berghei ANKA-GFP infection during pregnancy to evoke a prominent inflammatory response in the placenta that entails CD11b mononuclear infiltration, up-regulation of MIP-1 alpha chemokine and is associated with marked reduction of placental vascular spaces. Placenta pathology was associated with decreased fetal viability, intra-uterine growth retardation, gross post-natal growth impairment and increased disease severity in pregnant females. Moreover, we provide evidence that CSA and HA, known to mediate P. falciparum adhesion to human placenta, are also involved in mouse placental malaria infection. We propose that reduction of maternal blood flow in the placenta is a key pathogenic factor in murine pregnancy malaria and we hypothesize that exacerbated innate inflammatory responses to Plasmodium infected red blood cells trigger severe placenta pathology. This experimental model provides an opportunity to identify cell and molecular components of severe PAM pathogenesis and to investigate the inflammatory response that leads to the observed fetal and placental blood circulation abnormalities.     

Cellular accumulation of heat shock protein (Hsp) 72i in fetuses of trained rats

Forty-five Sprague-Dawley rats (60-80 days old) were randomly placed into one of three groups: sedentary pregnant control (PC); prepregnancy trained animals that exercised throughout pregnancy (PR); and nonpregnant trained animals (NPR). Each exercising animal ran at approximately 60-70% aerobic capacity (VO2max) for 1 hour/day up to and including day 18 of gestation (term = 21 days). On day 20 of gestation, fetuses were excised from each pregnant animal and scrutinized for gross abnormalities. In 3 randomly chosen fetuses from each litter, brain, heart, kidney, hind limb, and placental tissues were removed to assess the accumulation of the inducible isoform of the 70-kilodalton heat shock protein (Hsp 72i). No significant differences were detected between fetal hearts, hind limbs, or placental tissues of PC or PR groups. No Hsp 72i signal could be detected in fetal kidney or brain tissues from either pregnant group. Results indicate that maternal core temperature did not reach the threshold that would induce either gross fetal abnormalities or a fetal heat shock protein response. However, fetal and placental growth was reduced by the exercise protocol.     

The effect of human immunodeficiency virus-1 protease inhibitors on the toxicity of a variety of cells

Protease inhibitors in combination with other antiretroviral drugs have been shown to be efficacious in treating human immunodeficiency virus-1 (HIV-1) infection. The side effects of such a treatment usually involve perturbations of fat metabolism and insulin responsiveness. This has led to a number of studies on the adverse effects of these drugs in vitro. The concentrations of various protease inhibitors used in many of these studies were >20 microM. Although some investigators did address the toxicity of protease inhibitors, no overall effort was made to examine this effect during differentiation of fat or muscle. In this study, we assessed the toxicity of HIV-1 protease inhibitors over a range of concentrations (i.e., 0 to 100 microM) in nondifferentiating (e.g., human fibroblasts, 3T3-L1 preadipocytes, and L6 myoblasts) and differentiated cells (e.g., L6 myotubes). The most toxic protease inhibitor in all cell types was Saquinavir (sqv), whereas the least toxic protease inhibitor was Indinavir (idv). Ritonavir (rtv) and Amprenavir (apv) were more toxic than idv but not quite as toxic as sqv. In 3T3-L1 preadipocytes, treatment with sqv, rtv, and apv resulted in toxicity, whereas idv was not toxic even at the highest concentration used. Indinavir was not toxic to L6 myoblasts or L6 myotubes; however, sqv, rtv, and apv caused toxicity in L6 myoblasts. Saquinavir decreased L6 myotube viability in a dose-dependent manner. Human immunodeficiency virus-1 protease inhibitors were shown to be toxic in a variety of cell types. These effects on human fibroblasts and muscle cells have not been reported previously.     

The effect of hydroxyurea on the phosphorylation of zidovudine and lamivudine in human umbilical vein endothelial cells

Summary  The purpose of this study was to characterize the activation of zidovudine (ZDV) and lamivudine (3TC) in human umbilical vein endothelial cells (HUVEC) with and without hydroxyurea (HU) pretreatment. HUVEC were pretreated with HU or control media for 24 h and then incubated for an additional 3 h with ZDV or 3TC. Intracellular concentrations of parent drugs and the phosphorylated forms were determined by high-performance liquid chromatography. Pretreatment with HU resulted in more than a threefold increase in intracellular concentrations of total ZDV, with the major intracellular form being the monophosphate (>80%). The relative percentage of each ZDV form was similar between control and HU-treated cells. On the other hand, intracellular concentrations of total 3TC increased only slightly (14%) with HU pretreatment. Although the parent drug remained the major intracellular form of 3TC, there was nearly a 400% increase in the 3TC triphosphate after HU pretreatment. These data demonstrate that HU causes a large increase in the intracellular accumulation of total ZDV, whereas it increases total 3TC only slightly but improves its triphosphorylation. Given the increase in intracellular concentrations of ZDV monophosphate after HU pretreatment and that the monophosphate has no antiviral activity but is associated with toxicity, the use of HU is not a good strategy to improve ZDV activation in human endothelium. There is improved production of the active antiviral 3TC triphosphate with HU pretreatment. The combination may be beneficial in treating potential sanctuary sites such as endothelium.     

Maternal exposure to multi-wall carbon nanotubes does not induce embryo-fetal developmental toxicity in rats

BACKGROUND: Although the potential risk of carbon nanotubes (CNTs) to humans has recently increased due to expanding production and widespread use, the potential adverse effects of CNTs on embryo–fetal development have not yet been determined. METHODS: This study investigated the potential effects of multi‐wall CNTs (MWCNTs) on pregnant dams and embryo–fetal development in rats. MWCNTs were administered to pregnant rats by gavage at 0, 40, 200, and 1,000 mg/kg/day. All dams were subjected to Cesarean section on day 20 of gestation, and the fetuses were examined for any morphological abnormalities. RESULTS: All animals survived to the end of the study. A decrease in thymus weight was observed in the high dose group in a dose‐dependent manner. However, maternal body weight, food consumption, and oxidant–antioxidant balance in the liver were not affected by treatment with MWCNTs. No treatment‐related differences in gestation index, fetal deaths, fetal and placental weights, or sex ratio were observed between the groups. Morphological examinations of the fetuses demonstrated no significant difference in incidences of abnormalities between the groups. CONCLUSIONS: The results show that repeated oral doses of MWCNTs during pregnancy induces minimal maternal toxicity and no embryo–fetal toxicity at 1,000 mg/kg/day in rats. The no‐observed‐adverse‐effect level of MWCNTs is considered to be 200 mg/kg/day for dams and 1,000 mg/kg/day for embryo–fetal development. In this study, the dosing formulation was not analyzed to determine the degree of reaggregation (or not), nor were blood levels of CNT's measured in the dosed animals to verify or characterize absorption. Birth Defects Res (Part B) 92:69–76, 2011. © 2011 Wiley‐Liss, Inc.     

Advances in the development of novel antioxidant therapies as an approach for fetal alcohol syndrome prevention

Ethanol is the most common human teratogen, and its consumption during pregnancy can produce a wide range of abnormalities in infants known as fetal alcohol spectrum disorder (FASD). The major characteristics of FASD can be divided into: (i) growth retardation, (ii) craniofacial abnormalities, and (iii) central nervous system (CNS) dysfunction. FASD is the most common cause of nongenetic mental retardation in Western countries. Although the underlying molecular mechanisms of ethanol neurotoxicity are not completely determined, the induction of oxidative stress is believed to be one central process linked to the development of the disease. Currently, there is no known effective strategy for prevention (other than alcohol avoidance) or treatment. In the present review we will provide the state of art in the evidence for the use of antioxidants as a potential therapeutic strategy for the treatment using whole‐embryo and culture cells models of FASD. We conclude that the imbalance of the intracellular redox state contributes to the pathogenesis observed in FASD models, and we suggest that antioxidant therapy can be considered a new efficient strategy to mitigate the effects of prenatal ethanol exposure. Birth Defects Research (Part A) 103:163–177, 2015. © 2014 Wiley Periodicals, Inc.     

Effect of prematuration, meiosis activating sterol and enriched maturation medium on the nuclear maturation and competence to development of calf oocytes

New strategies were proposed to improve the developmental competence of calf oocytes through in vitro technologies. Cumulus-oocyte complexes were first prematured for 24 h in the presence of meiosis inhibitors. Both Roscovitine alone (50 microM) or in combination with Butyrolactone-I (12.5 microM Rosco+6.25 microM BL-I) prevented the progression of meiosis. Their effect on nuclear maturation was reversible after a further 17 or 24 h maturation step. However, a dramatic decrease in embryo development was observed after fertilization (abattoir oocytes: 4-9% blastocyst rate versus 14-17% for control embryos). Similar results were obtained with oocytes collected by Ovum Pick Up from living donors. No pregnancy was obtained after single transfer of two blastocysts obtained from prematured oocytes (0/2 versus 4/12 for control embryos). Adding low concentrations (1, 3 or 10 microM) of follicular fluid-meiosis activating sterol (FF-MAS) during the maturation step had a beneficial effect on nuclear maturation (73-86% metaphase II versus 58% for control oocytes). However, subsequent embryo development was not improved. Enriching the maturation medium, namely with hormones, growth factors and precursors of glutathione, induced a sixfold increase in glutathione in the oocyte and had a beneficial effect on embryo development (38% increase in blastocyst rate). In conclusion, in opposition to the results reported with adult oocytes, prematuring calf oocytes had a negative impact on their developmental potential. Although FF-MAS improved nuclear maturation, its addition in the maturation medium did not increase embryo development. However, enriching the maturation medium had a positive effect on embryo development, indicating that cytoplasmic maturation was improved.     

Exercise and fetal health

This is a brief review of current information dealing with the impact of maternal exercise on the well-being of the human embryo and fetus. It discusses the theoretical concerns and exercise variables involved in the interaction between exercise and fetal health and focuses on five areas of fetal health where some information is available describing the interaction in the human. These include embryonic development, fetoplacental growth, prematurity, indices of fetal stress/distress, and condition during labor and at birth. It concludes that well-conditioned women who continue a regular running or aerobics regimen in the peri-conceptual period and throughout pregnancy at levels that exceed current guidelines do not experience an increase in the incidence of failure to conceive, abortion, congenital abnormalities, abnormal placentation, premature rupture of the membranes or preterm labor. Although all their fetuses demonstrate a brisk elevation in heart rate post-exercise throughout pregnancy, they have a significant reduction in the incidence of 4 clinical markers of fetal stress/distress during labor. In addition, at the time of delivery, their % body fat is less than that of the control offspring (11 vs 16%) which accounts for over 70% of the observed 300 g reduction in birthweight. Finally, there is little evidence to suggest that the other exercise regimens studied to date have an adverse effect on fetal health.     

Deregulation of the serum- and glucocorticoid-inducible kinase SGK1 in the endometrium causes reproductive failure

Infertility and recurrent pregnancy loss (RPL) are prevalent but distinct causes of reproductive failure that often remain unexplained despite extensive investigations. Analysis of midsecretory endometrial samples revealed that SGK1, a kinase involved in epithelial ion transport and cell survival, is upregulated in unexplained infertility, most prominently in the luminal epithelium, but downregulated in the endometrium of women suffering from RPL. To determine the functional importance of these observations, we first expressed a constitutively active SGK1 mutant in the luminal epithelium of the mouse uterus. This prevented expression of certain endometrial receptivity genes, perturbed uterine fluid handling and abolished embryo implantation. By contrast, implantation was unhindered in Sgk1-/- mice, but pregnancy was often complicated by bleeding at the decidual-placental interface and fetal growth retardation and subsequent demise. Compared to wild-type mice, Sgk1-/- mice had gross impairment of pregnancy-dependent induction of genes involved in oxidative stress defenses. Relative SGK1 deficiency was also a hallmark of decidualizing stromal cells from human subjects with RPL and sensitized these cells to oxidative cell death. Thus, depending on the cellular compartment, deregulated SGK1 activity in cycling endometrium interferes with embryo implantation, leading to infertility, or predisposes to pregnancy complications by rendering the feto-maternal interface vulnerable to oxidative damage.     

Effect of oxygen concentration in the incubator's gas phase on the development of cultured preimplantation rabbit embryos

Development of rabbit preimplantation embryos cultured under 20, 5 or 1% oxygen was studied. Three-day-old morulae were cultured in a protein-free medium (BSM II supplemented with 5 mg PVP/ml medium) for 24 and 48 h. Embryonic development was evaluated by gross morphology and by incorporation of tritiated thymidine as an indicator of cell proliferation. The lower oxygen concentrations yielded significantly better embryo development at 24 and at 48 h than the 20% concentration. There was no significant difference in development between 5% and 1% oxygen. Addition of the radical scavanger superoxiddismutase (SOD), either alone or in combination with catalase or reduced glutathione, did not improve embryo development even in the 20% oxygen group. Our data suggest the need to reduce in vitro oxygen levels from 20% to more physiological concentrations.     

Cost-Effectiveness of Tenofovir Instead of Zidovudine for Use in First-Line Antiretroviral Therapy in Settings without Virological Monitoring

Background

The most recent World Health Organization (WHO) antiretroviral treatment guidelines recommend the inclusion of zidovudine (ZDV) or tenofovir (TDF) in first-line therapy. We conducted a cost-effectiveness analysis with emphasis on emerging patterns of drug resistance upon treatment failure and their impact on second-line therapy.

Methods

We used a stochastic simulation of a generalized HIV-1 epidemic in sub-Saharan Africa to compare two strategies for first-line combination antiretroviral treatment including lamivudine, nevirapine and either ZDV or TDF. Model input parameters were derived from literature and, for the simulation of resistance pathways, estimated from drug resistance data obtained after first-line treatment failure in settings without virological monitoring. Treatment failure and cost effectiveness were determined based on WHO definitions. Two scenarios with optimistic (no emergence; base) and pessimistic (extensive emergence) assumptions regarding occurrence of multidrug resistance patterns were tested.

Results

In the base scenario, cumulative proportions of treatment failure according to WHO criteria were higher among first-line ZDV users (median after six years 36% [95% simulation interval 32%; 39%]) compared with first-line TDF users (31% [29%; 33%]). Consequently, a higher proportion initiated second-line therapy (including lamivudine, boosted protease inhibitors and either ZDV or TDF) in the first-line ZDV user group 34% [31%; 37%] relative to first-line TDF users (30% [27%; 32%]). At the time of second-line initiation, a higher proportion (16%) of first-line ZDV users harboured TDF-resistant HIV compared with ZDV-resistant viruses among first-line TDF users (0% and 6% in base and pessimistic scenarios, respectively). In the base scenario, the incremental cost effectiveness ratio with respect to quality adjusted life years (QALY) was US$83 when TDF instead of ZDV was used in first-line therapy (pessimistic scenario: US$ 315), which was below the WHO threshold for high cost effectiveness (US$ 2154).

Conclusions

Using TDF instead of ZDV in first-line treatment in resource-limited settings is very cost-effective and likely to better preserve future treatment options in absence of virological monitoring.     

Zygote donor nitrogen metabolism and in vitro embryo culture perturbs in utero development and IGF2R expression in ovine fetal tissues

Tests were made of the effects of altering nitrogen metabolism in zygote donor ewes on fetal development and expression of the gene encoding the type II insulin-like growth factor receptor (IGF2R) following the transfer of ovine embryos cultured from these zygotes, either in the absence or presence of serum. Zygotes, recovered from superovulated ewes (32 on a urea supplemented (30 g urea/kg) diet (high N) and 32 on a control diet (low N)) 36 h after intrauterine AI using semen from a single sire, were cultured for 5 days in synthetic oviductal fluid (SOF) media either with BSA and amino acids (SOF-) or with 10% (v/v) steer serum (SOF+). In total, 166 embryos, including 30 in vivo controls, were transferred singly at day 6 post-AI to synchronous recipients and the products of conception recovered at day 125 of gestation. Elevated plasma urea concentrations in zygote donors were associated with accelerated early embryo development, low pregnancy rates (16%) for embryos from the high N, SOF+ treatment, and significantly influenced fetal development and the expression of IGF2R in the fetal heart at day 125 of gestation. Importantly, the culture of sheep zygotes under serum-free conditions led to a high incidence of aberrant conceptus development and IGF2R expression. Consequently, maternal nitrogen metabolism prior to zygote recovery and in vitro culture can influence fetal development and the expression of an imprinted gene following embryo transfer, and these data support the notion that environmental effects on the follicle-enclosed oocyte may contribute to the etiology of the Large Offspring Syndrome.     

Valproic acid developmental toxicity and pharmacokinetics in the rhesus monkey: an interspecies comparison

This study was undertaken to assess the developmental toxicity and drug distributional and metabolic characteristics of prenatal valproic acid (VPA) exposure in rhesus monkeys. Oral administration of 20-600 mg/kg/day VPA (approximately 1-15 X human therapeutic dose) to 33 animals on variable gestational days (GD) during organogenesis resulted in dose-dependent developmental toxicity manifested as increased embryo/fetal mortality, intrauterine growth retardation, and craniofacial and skeletal defects. Biphasic plasma elimination curves were observed for total and free VPA on the first (GD 21) and last (GD 50) days of treatment in the 100- and 200-mg/kg/day dose groups. VPA exhibited dose-independent elimination kinetics at the plasma concentrations observed in this study. There was no significant change in pharmacokinetic parameters (maternal plasma elimination rate, area under the curve, peak plasma concentration) between the first and last days of treatment at either dose level. Placental transfer studies indicated that embryos were exposed to half the free VPA concentrations present in maternal plasma on GD 37. Comparisons of interspecies sensitivity to VPA-induced developmental toxicity in the mouse, rat, monkey, and man are made.     

A rational approach in the search for potent inhibitors against HIV proteinase

Synthetic peptides described as dog renin inhibitors were found to effectively inhibit the aspartyl protease of human immunodeficiency virus (HIV). The selection of oligopeptides for the HIV protease inhibition study was based on 1) the current strategy of inhibiting aspartyl proteases with transition state analogs, and 2) our previous observations regarding optimal structural differentiation at the P2 position among human, dog, and rat renin inhibitors. In an in vitro assay system consisting of recombinant HIV protease and a synthetic decapeptide substrate (at pH 5.5), results show that HIV protease was unaffected by statine-containing analogs carrying histidine at the P2 position whereas analogs containing valine at the same position yielded anti-protease IC50 values ranging from 50 to 500 nM. As anticipated, some analogs were also shown to inhibit processing of recombinant polyprotein substrate by HIV protease in vitro. The anti-viral activity of three inhibitors was studied in HIV-infected CEM and MT-2 cells. Results showed that one compound, Ac-Naphthylalanyl-Pro-Phe-Val-Statine-Leu-Phe-NH2 (antiprotease IC50 value = 0.4 microM), protected the infected cells effectively with IC50 values (0.73 microM for CEM cells and 0.88 microM for MT-2 cells). This antiviral effect is comparable to those obtained with AZT and ddC in parallel studies of MT-2 cells.     

Ammonium induces aberrant blastocyst differentiation,metabolism, pH regulation,gene expression and subsequently alters fetal development in the mouse

The presence of ammonium in the culture medium has significant detrimental effects on the regulation of embryo physiology and genetics. Ammonium levels build up linearly over time in the culture medium when media containing amino acids are incubated at 37 degrees C. Ammonium in the culture media significantly reduces blastocyst cell number, decreases inner cell mass development, increases apoptosis, perturbs metabolism, impairs the ability of embryos to regulate intracellular pH, and alters the expression of the imprinted gene H19. In contrast, the rate of blastocyst development and blastocyst morphology appear to be normal. The transfer of blastocysts exposed to ammonium results in a significant reduction in the ability to establish a pregnancy. Furthermore, of those embryos that manage to implant, fetal growth is significantly impaired. Embryos exposed to 300 microM ammonium are retarded by 1.5 days developmentally at Day 15 of pregnancy. It is therefore essential that culture conditions for mammalian embryos are designed to minimize the buildup of ammonium to prevent abnormalities in embryo physiology, genetic regulation, pregnancy, and fetal development.     

Inhibitors of choline uptake and metabolism cause developmental abnormalities in neurulating mouse embryos.

BACKGROUND: Choline is an essential nutrient in methylation, acetylcholine and phospholipid biosynthesis, and in cell signaling. The demand by an embryo or fetus for choline may place a pregnant woman and, subsequently, the developing conceptus at risk for choline deficiency. METHODS: To determine whether a disruption in choline uptake and metabolism results in developmental abnormalities, early somite staged mouse embryos were exposed in vitro to either an inhibitor of choline uptake and metabolism, 2-dimethylaminoethanol (DMAE), or an inhibitor of phosphatidylcholine synthesis, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH(3)). Cell death following inhibitor exposure was investigated with LysoTracker Red and histology. RESULTS: Embryos exposed to 250-750 microM DMAE for 26 hr developed craniofacial hypoplasia and open neural tube defects in the forebrain, midbrain, and hindbrain regions. Embryos exposed to 125-275 microM ET-18-OCH(3) exhibited similar defects or expansion of the brain vesicles. ET-18-OCH(3)-affected embryos also had a distended neural tube at the posterior neuropore. Embryonic growth was reduced in embryos treated with either DMAE (375, 500, and 750 microM) or ET-18-OCH(3) (200 and 275 microM). Whole mount staining with LysoTracker Red and histological sections showed increased areas of cell death in embryos treated with 275 microM ET-18-OCH(3) for 6 hr, but there was no evidence of cell death in DMAE-exposed embryos. CONCLUSIONS: Inhibition of choline uptake and metabolism during neurulation results in growth retardation and developmental defects that affect the neural tube and face.     

Effect of simultaneous administration of betamethasone and triiodothyronine (T3) on the development of functional pulmonary maturation in fetal rabbit

Recent experimental evidence suggests that a combination of glucocorticoid and thyroid hormone may be more effective than either hormone alone in accelerating morphologic as well as biochemical mammalian fetal lung maturation. We have demonstrated that IM administration of T3 to the rabbit doe is associated with enhanced functional fetal lung maturation. We investigated the effect of simultaneous administration of T3 and betamethasone on the development of functional fetal lung maturation and the duration of survival after premature delivery. On day 25 and 26 of pregnancy, T3 (175 micrograms/kg/dose) betamethasone (85 micrograms/kg/dose), T3 plus betamethasone or the appropriate amount of the vehicles were injected. The functional fetal pulmonary maturity and the duration of survival after premature delivery were assessed on day 27 of gestation. Although enhanced functional fetal lung maturation was observed after T3 or betamethasone administration, there was no additive effect after simultaneous administration of both. The duration of survival on premature delivery was enhanced in betamethasone but not T3 or T3 plus betamethasone group when compared to control. Further animal experimentation seems necessary before a clinical trial of T3 plus betamethasone therapy is considered.